Process of purifying liquids.



FREDERICK RICHARD BACHLER, F LOS KIESELGUHR COMPANY OF AMERICA, PORATION OF CALIFORNIA.

ANGELES, CALIFORNIA, ASSIGNOR TO 0F LOS ANGELES, CALIFORNIA, A COR- PROCESS OF PURIFYING' LIQUIDS.

Specification of Letters Patent. Patented Feb, 8, 1916,

Application filed March 1, 1915. Serial No. 11,150.

No Drawing.

To all whom it may concern: itate,so as to maintain it in a porous, open Be it known that I, FREDERICK RICHARD condition, suitable for filtration, and I pre- BACHLER, a subject of the Emperor of 'Ausfer to use kieselguhr as such porous carrier, tria-Hungary, residing at Los Angeles, in by reason of its exceptional porosity and the county of Los Angeles and State of Galability to maintain the openness of the preifornia, have invented a new and useful cipitate.

Process of Purifying Liquids, of which the As a colloidal metallic compound, or minfollowing is a specification. oral colloid. I have used. with satisfactory This invention relates to a process for the results, a colloidal clay or hydrous alumiremoval from liquids, of impurities present num silicate, sufficiently colloidal to enable therein, and the main object of the invention it to remain suspended in water for an inis to provide for removal of impurities definite time, when added to the water in 5 which interfere with or retard filtration of the proportions required by the process, say liquids. in the proportion of one-tenth part of clay Another object of the inyention is-to proto one hundred parts of water. Any other vide for clarification and decolorization of suitable colloidal metallic compound or minliquid Q eral colloid may, however, be used.

A further object of the invention is to As a porous carrier I prefer to use kieselremove or reduce viscosity or stickiness of guhr, ground, or otherwise reduced to a the liquids, as an aid-to crystallization. state of suitably fine division. Any other I will hereinafter describe my invention suitable porous carrier may however be in its particular application to the treatment used, 1n some cases, for example, sawdust, of sugar solutions, with a view to aiding sand or other solid inert material in a suitfiltration, decolorization and reduction of able state of division. viscosity, but it will be understood that the In order to facilitate the uniform and invention is of general application, to solurapid introduction of the collodial metallic tions, or liquids, containing substances, such compound or mineral colloid and the porous 0 as gummy or slimy matters, which intercarrier 1nto the solution or liquid, I prefer fere with the satisfactory treatment of the to mix the colloidal metallic compound 0r solution or liquid, in filtration, decantation, mineral colloid and porous carrier together zrystallization, or otherwise separating the to form a uniform mixture suitable for use :onstituents thereof. 1l1 0&II' VlI1g out my process. My compo- This invention is based on the action, in s1t1on for treatment of solutions may be auch solutions or liquids, of a colloidal made by grinding or reducing each of the netallic compound or mineral colloid, such stated constituents, namely the colloidal LS colloidal clay, colloidal hydrous alumimetallic compound or mineral colloid and mm silicate, or aluminum hydrate, which the porous carrier, to a state of suitably fine s brought into a state of suspension in the division, and intimately mixing such divided lolution or liquid, and is then precipitated .materials to form a substantially uniform y the action of a suitable coagulating agent, I product. In case clay and kieselg-uhr are orming a flocculent precipitate which sepused as the ingredients of the composition, rates, from the solution or liquid, the dark such composition may be composed of subolored gummy substance which it is desired stantially equal parts of clay and kieselguhr. o eliminate. In order to enable this clarify- I will describe my process as applied to rig operation to be carried out to advanthe clarification of sugar solutions by the use age, I have found it generally desirable to of a composition of clay and kieselguhr, it so in connection therewith a substance being understood that in applying it to the hich will prevent clogging of the filter clarification of other liquids, or with suburing the subsequent filtration, by reason stitutes for either the clay or the kieselguhr, f the large amount of this precipitate and substantially the same course may be fol- 1e gummy matter contained therein. For lowed, with suitable changes as to propor- 1is purpose I may use any material capable tions, temperature, etc., that may be re f acting as a porous carrier for the precipthe liquid being quired by the nature of treated. or the nature of the colloidal material or its carrier.

The mixture of colloidal clay and kicsclguhr is made into a thick cream by triturating it with a little water, and the resulting cream is their added to the sugar solution to be treated, and thoroughly mixed or incorporated therewith, the proportion of clay to solution being, for example, about one tenth of one per cent., or more, according to the strength of the solution and the amount of impurities present. The clay on account of its colloidal nature, becomes suspended in the solution in particles of extreme fineness, and remains so suspended until precipitated bv the action of a suitable coagulator or flocculator. The nature of the coagulating agent used may depend on the nature of the solution which is being treated. With cane sugar solution, I have obtained satisfactory results by the use of an organic colloid, for example, a protein emulsion or jelly, such as flaxseed or cottonseed meal, boiled with sufficient water to form a gelatinous fluid. This fluid is added to the solution containing the colloidal clay, sufficient emulsion being preferably used to precipitate substantially all of the clay as a flocculent precipitate. The solution is heated to a temperature ofabout 50 or 60 degrees centigrade during the precipitating operation. The fiocculent precipitate so formed contains the kieselguhr together with the clay and with a considerable proportion of the impurities in the solution, which are carried down with the clay, such precipitated impurities including particularly the gummy matters which tend to interfere with filtration. These gummy matters as well as the finely divided clay are so held and sup ported by the kieselguhr, acting as a porous carrier, that the precipitate maintains an open porous condition which is well adapted filtration or decantation. The ,solution is then treated, by filtration, decantation, or both, so as to remove the precipitate therefrom. The porosity of the precipitate enables it to be removed with especial economy and advantage in filte'i presses, as the porosity of the filter-cake is maintained and the clogging of the filter cloths is reduced to a minimum. I have found that in this process, all, or substantially all, of the clay used in the process is precipitated, and that it carries down with it about 25 per cent. of the mineral matter (ash) present in the solution together with about 12 to 18 per cent. of the organic impurities present, and that the organic matters so removed are largely of a gummy nature and such as would interfere with filtration. As such organic matters are usually of a dark color, their removal produces a considerable decolorizing effect. The removal of these gummy matters also considerably reduces the viscosity of the solution and therefore aids the subsequent crystallization of sugar from the solution.

Instead oi. a colloid as a coagulating agent, I may, in some cases, use a crystalloid, for example, sulfate of alumina, alum, or phosphoric acid. Thus, in treating beet sugar solutions, phosphoric acid may be used to advantage, particularly where the. colloidal metallic compound used contains small amounts of alkali, as I have found sometimes to'be the case with the colloidal clay, the phosphoric acid serving to neutralize such alkali. In some cases silicate of. soda may also be added to the colloidal metallic compound to increase its colloidal action, and an equivalent amount of phosphoric acid may then be added, so as to react with this silicate of soda, forming an alkali phosphate and precipitating silica in bulky form, which aids the precipitating action of the coagulated colloidal compound. The alkali phosphate so formed will set free lime, from salts that are formed from organic acids and the lime used in the usual operations, and such organic acids being often darkly colored, and of a colloidal nature, are brought down with the colloidal metallic compound in the coagulating action, thereby aiding in decolorization and the reduction of viscosity.

My invention is applicable to other liquids besides sugar solutions. For example, it may be used for purifying water for drinking purposes, for purifying vegetable or mineral oils, and in general for purifying any liquid containing a gummy matter or other substance which interferes with filtration. In applying the invention to such various uses, the nature of the colloidal metallic compound, the coagulating agent therefor, and the porous carrier material, may be Varied in order to produce the best results, and the process may be otherwise varied in its several steps. For example, in some cases, the use of heat in the coagulating action may not be necessary.

While I prefer to carry out the process by adding the porous carrier along with the colloidal metallic compound or mineral colloid or before the precipitation of such compound by the coagulating agent, such porous carrier may, if desired. be added to the solution or liquid after the precipitation of the colloidal metallic compound or mineral colloid by the coagulating agent, said porous carrier being then mixed thoroughly with the precipitate preparatory to filtration.

hat I claim is:

1. The process of purifying a liquid which consists in mixing therewith a colloidal metallic compound, precipitating such compound, togm'hcr with impurities in the liquid, by the action of a coagulating agent, and incorporating with the solution, luring the process, a porous carrier to proiuce an open precipitate.

2. The process of purifying liquids, which :onsists in mixing with such liquid, a. minaral colloid together with a porous carrier naterial, adding a coagulating agent to the .iquid to precipitate the mineral colloid ;ogether with impurities in the liquid and with the porous carrier material, and then removing the precipitate from the liquid.

3. The process of purifying liquids, which :onsists in mixing with the liquid, a mineral :olloid together With a porous carrier mate- -ial, heating the liquid and adding a coaguating agent to precipitate the colloidal netallic compound together with impuriies in the liquid and with the porous car- 'ier material, and then filtering the liquid.

4:. The process of purifying sugar soluions which consists in mixing a colloidal material containing hydrous aluminum siliate with such solution, precipitating such olloidal material, together with impuriies in the solution, by the action of a oagulating agent in the presence of heat, ucorporating kieselguhr with the solution filtering such precipitate from p the colloidal clay together with impurities in the liquid and with the porous carrier material, and then removing the precipitate from the liquid.

In testimony whereof I have hereunto set my hand, at Habana, Cuba, this 21st day of January 1915;

FREDERICK RICHARD BACHLER.

Witnesses:

RAoUL F. WASHINGTON, J. A. SPRINGER. 

